For the past 4 years we have pursued the primary objective of this study: to determine the relationship of cardiovascular (CVD) risk factors to cognitive decline in the elderly. A total of 733 surviving male members (mean age=76.1 years) of the Western Collaborative Group Study were assessed on several global and specific measures of neuropsychological functioning. Since the role of CVD risk factors for abnormal cognitive aging in women is generally understudied, we added 558 older women to our study (277 examined and 281 by questionnaire; mean age=71.2 years). Taking maximum advantage of the previously and recently collected data has resulted in 25 published, presented, or submitted papers. Additionally, a number of analyses (presented in the Progress Report) support the conclusion of both cross-sectional and longitudinal associations between higher levels of blood pressure and lower levels of neuropsychological performance. These findings, however, and those of others in the literature, are based on the measurement of single-point resting blood pressures and do not take into account other aspects of blood pressure measured continuously over the course of a typical day. Since these characteristics have a stronger relationship to both cardiovascular and cerebrovascular end organ damage than do resting levels, we propose in this application to continue our examination of the BP-cognition association with the use of noninvasive ambulatory blood pressure monitoring over the course of 16 hours. The major objective will be to characterize both BP levels and variability during the day and night in 450 male and female subjects (age range=74 to 90 years) examined previously in the last round of examinations. Given that sleep-disordered breathing increases in prevalence with age and may result in both elevated nighttime blood pressure levels and variability as well as lower levels of neuropsychological performance, we also seek to characterize the presence or absence of significant apneic events (by noninvasive ambulatory in-home assessments) and test its mediating effect on the blood pressure-cognition association. A secondary set of analyses will utilize the biological and neuropsychological data collected in the 1992- 94 round of examinations (a total of 1,010 male and female subjects) to determine prospective relationships of blood pressure, neuropsychological functioning, and symptoms of sleep apnea with subsequent 5-year mortality. Completion of the research plan described herein will enable us, for the first time, to extend the findings obtained for single-point resting blood pressures to repeated measurements of blood pressure during both day and night. Accounting for the multifactorial nature of influences such as sleep apnea on both blood pressure and neuropsychological functioning in the elderly represents a unique and important advance of our study, suggesting new avenues to prevent or slow the rate of neuropsychological decline and premature mortality in the elderly.